Room-Temperature,Metal-Free,and One-Pot Preparation of 2H-Indazoles through a Mills Reaction and Cyclization Sequence

The Mills reaction and cyclization of readily available 2-aminobenzyl alcohols and nitrosobenzenes using thionyl bromide provided 2H-indazoles in up to 88 % yields. In the metal-free process, acetic acid played a crucial role for the both Mills reaction and cyclization. A brominated 2H-indazole could also be obtained through the one-pot sequence.     

Effects of polyethylene spacer length in polymeric electrolytes on gelation of ionic liquids and ionogel properties

Polymer electrolytes containing N,N′-(trans-cyclohexane-1,4-diyl)dibenzamide linkages, polyethylene ((CH₂)_m, m = 2, 4, 10) spacers, and bis(trifluoromethanesulfonyl)amide (TFSA) or bis(fluorosulfonyl)amide (FSA) counteranions (polymer abbreviation: CDBAm•X; m = 2, 4, 10; X = TFSA, FSA) have been synthesized, adding to our previous report (m = 6). In addition, their ability to effect the gelation of six ionic liquids and the properties of the resulting ionogels have been examined. The polymers, except for CDBA10•TFSA, effect the gelation for all ionic liquids used in this study at fairly low concentrations (0.9–50 g/L). Ionogel ionic conductivity is not dependent on the spacer length, but does decrease slightly as increasing amounts of the gelatinizer are introduced. In contrast to ionic conductivity, the temperatures at which these ionogels transition into isotropic fluids is dependent on the spacer length; the gel composed of [EMI][FSA] and 100 g/L of CDBA6•FSA transforms at 120 °C, while the gel composed of [EMI][FSA] and 5 g/L of CDBA2•FSA does not transform into a sol even when temperatures become 155 °C. In brief, ionogel heat resistance can be improved by changing the spacer length of the polyelectrolyte. Finally, it has been determined using cyclic voltammetry that the potential window of the polyelectrolytes is particularly wide, ranging from −1.6 to 2.5 V. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 249–255     

On the six-field model of fluids based on extended thermodynamics

We study the six-field model of fluids (ET6) derived from extended thermodynamics. The six fields are the mass density, the velocity, the temperature, and the dynamic pressure (nonequilibrium pressure). We present the basic system of field equations of ET6. And we elucidate its characteristic features through the studies of the singular limit from polyatomic to monatomic rarefied gases, of hydrodynamic fluctuation, and of a hard-sphere system. Open problems remained in ET6 at present are also pointed out.     

NMR‐based analysis of the chemical composition of Japanese persimmon aqueous extracts

Japanese persimmon (Diospyros kaki L.) is recognized as an outstanding source of biologically active compounds relating to many health benefits. In the present study, NMR spectroscopy provided a comprehensive metabolic overview of Japanese persimmon juice. Detailed signal assignments of Japanese persimmon juice were carried out using various 2D NMR techniques incorporated with broadband water suppression enhanced through T₁ effects (BB‐WET) or WET sequences, and 26 components, including minor components, were identified. In addition, most components were quantitatively evaluated by the integration of signals using conventional ¹H NMR and BB‐WET NMR. This is the first detailed analysis combined with quantitative characterization of chemical components using NMR for Japanese persimmon. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis of the N-Amykitanosyl Tetramic Acid Moiety of Amycolamicin

An improved five-step synthetic route from l -fucose to an N-glycosyl l -valine methyl ester has been developed. The new route involves glycosidation of l -fucose with phenol in a β-selective manner without protection/deprotection steps and one-pot stereochemical inversion of a secondary alcohol intermediate and is superior to our previous one both in the number of steps and in overall yield. An N-glycosyl l -valine benzyl ester, prepared from l -fucose in an analogous way, has been elaborated into an N-amykitanosyl tetramic acid derivative, Li's synthetic intermediate for amycolamicin, via a four-step sequence which features the utilization of Bestmann's ylide to stereoconvergently construct an N-glycosyl tetramic acid intermediate in a single step, opening of a cyclic carbonate ring with an amine to regioselectively install a carbamate functionality, and visible light-mediated oxidative debenzylation of an N,N-dibenzyl carbamate.     

Cross‐sectional structural characterization of the surface of exfoliated HOPG using HRTEM‐EELS

We analyzed the surface atomic structure of highly oriented pyrolytic graphite (HOPG) substrate exfoliated with adhesive tape, using high‐resolution transmission electron microscopy and scanning transmission electron microscopy‐electron energy‐loss spectroscopy (STEM‐EELS). The surface step height of the exfoliated HOPG substrate was determined using high‐angle annular dark‐field‐scanning transmission electron microscopy (HAADF‐STEM) images and the depth profiles of the EELS spectra of a cross‐sectioned thin foil specimen prepared via focused ion beam milling. The exfoliated surface of the HOPG substrate presented disordered and curved graphene layers. The STEM‐EELS measurements indicated that upon exfoliation, the surface of the HOPG substrate reacted with atmospheric water and oxygen molecules.     

Catalytic Enantioselective Reaction of α‐Phenylthioacetonitriles with Imines Using Chiral Bis(imidazoline)–Palladium Catalysts

The catalytic enantioselective reaction of α‐phenylthioacetonitriles with imines has been developed. The reaction of various imines proceeds in good yields and diastereo‐ and enantioselectivities in the presence of chiral bis(imidazoline)–palladium catalysts. The obtained products can be converted into β‐aminonitrile or β‐aminoamide compounds without loss of enantiopurity.